ABSTRACT
Noroviruses are a leading cause of acute gastroenteritis (AGE) among adults and children worldwide. NoroSurv is a global network for norovirus strain surveillance among children <5 years of age with AGE. Participants in 16 countries across 6 continents used standardized protocols for dual typing (genotype and polymerase type) and uploaded 1,325 dual-typed sequences to the NoroSurv web portal during 2016-2020. More than 50% of submitted sequences were GII.4 Sydney[P16] or GII.4 Sydney[P31] strains. Other common strains included GII.2[P16], GII.3[P12], GII.6[P7], and GI.3[P3] viruses. In total, 22 genotypes and 36 dual types, including GII.3 and GII.20 viruses with rarely reported polymerase types, were detected, reflecting high strain diversity. Surveillance data captured in NoroSurv enables the monitoring of trends in norovirus strains associated childhood AGE throughout the world on a near real-time basis.
Subject(s)
Caliciviridae Infections , Gastroenteritis , Norovirus , Adult , Child , Genotype , Humans , Liver , PhylogenyABSTRACT
Human noroviruses cause an estimated 685 million infections and 200â 000 deaths annually worldwide. Although vaccines against GII.4 and GI.1 genotypes are under development, no information is available regarding vaccines or monoclonal antibodies to other noroviral genotypes. Here, we developed 2 variable-domain llama heavy-chain antibody fragment (VHHs) clones, 7C6 and 1E4, against GII.4 and GII.17 human noroviruses, respectively. Although 7C6 cross-reacted with virus-like particles (VLPs) of GII.17, GII.6, GII.3, and GII.4, it neutralized only GII.4 norovirus. In contrast, 1E4 reacted with and neutralized only GII.17 VLPs. Both VHHs blocked VLP binding to human induced pluripotent stem cell-derived intestinal epithelial cells and carbohydrate attachment factors. Using these 2 VHHs, we produced a heterodimeric VHH fragment that neutralized both GII.4 and GII.17 noroviruses. Because VHH fragments are heat- and acid-stable recombinant monoclonal antibodies, the heterodimer likely will be useful for oral immunotherapy and prophylaxis against GII.4 and GII.17 noroviruses in young, elderly, or immunocompromised persons.
Subject(s)
Antibodies, Monoclonal/immunology , Caliciviridae Infections/prevention & control , Capsid Proteins/immunology , Immunization, Passive/methods , Immunoglobulin Fragments/immunology , Antibodies, Monoclonal/administration & dosage , Antibodies, Viral/immunology , Caliciviridae Infections/immunology , Caliciviridae Infections/virology , Capsid Proteins/genetics , Cross Reactions , Epitopes/immunology , Humans , Immunoglobulin Fragments/administration & dosage , Induced Pluripotent Stem Cells/immunology , Norovirus/drug effects , Norovirus/genetics , Norovirus/immunology , Recombinant Proteins/immunologyABSTRACT
Seven foodborne norovirus outbreaks attributable to the GII.P17-GII.17 strain were reported across Japan in 2017, causing illness in a total of 2,094 persons. Nori (dried shredded seaweed) was implicated in all outbreaks and tested positive for norovirus. Our data highlight the stability of norovirus in dehydrated food products.
Subject(s)
Caliciviridae Infections/virology , Disease Outbreaks , Food Microbiology , Norovirus/isolation & purification , Porphyra/virology , Caliciviridae Infections/epidemiology , Humans , Japan/epidemiologyABSTRACT
During the 2016-17 winter season in Japan, human norovirus GII.P16-GII.2 strains (2016 strains) caused large outbreaks of acute gastroenteritis. Phylogenetic analyses suggested that the 2016 strains derived from the GII.2 strains detected during 2010-12. Immunochromatography between 2016 strains and the pre-2016 GII.2 strains showed similar reactivity.
Subject(s)
Caliciviridae Infections/epidemiology , Caliciviridae Infections/virology , Norovirus/genetics , Norovirus/immunology , Phylogeny , Adolescent , Child , Child, Preschool , Disease Outbreaks , Gastroenteritis/epidemiology , Gastroenteritis/virology , Humans , Infant , Infant, Newborn , Japan/epidemiology , Seasons , Young AdultABSTRACT
Residents of long-term care facilities for the elderly are vulnerable to health care-associated infections. However, compared to medical institutions, long-term care facilities for the elderly lag behind in health care-associated infection control and prevention. We conducted a epidemiologic study to clarify the current status of infection control in long-term care facilities for the elderly in Japan. A questionnaire survey on the aspects of infection prevention and control was developed according to SHEA/APIC guidelines and was distributed to 617 long-term care facilities for the elderly in the province of Osaka during November 2016 and January 2017. The response rate was 16.9%. The incidence rates of health care-associated infection outbreaks and residents with health care-associated infections were 23.4 per 100 facility-years and 0.18 per 1,000 resident-days, respectively. Influenza and acute gastroenteritis were reported most frequently. Active surveillance to identify the carrier of multiple drug-resistant organisms was not common. The overall compliance with 21 items selected from the SHEA/APIC guidelines was approximately 79.2%. All facilities had infection control manuals and an assigned infection control professional. The economic burdens of infection control were approximately US$ 182.6 per resident-year during fiscal year 2015. Importantly, these data implied that physicians and nurses were actively contributed to higher SHEA/APIC guideline compliance rates and the advancement of infection control measures in long-term care facilities for the elderly. Key factors are discussed to further improve the infection control in long-term care facilities for the elderly, particularly from economic and social structural standpoints.
Subject(s)
Cross Infection/prevention & control , Disease Outbreaks/prevention & control , Homes for the Aged/standards , Infection Control/standards , Nursing Homes/standards , Aged , Cross Infection/economics , Cross Infection/epidemiology , Disease Outbreaks/economics , Gastroenteritis/economics , Gastroenteritis/epidemiology , Gastroenteritis/prevention & control , Homes for the Aged/economics , Humans , Incidence , Infection Control/economics , Influenza, Human/economics , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Japan/epidemiology , Long-Term Care , Nursing Homes/economics , Surveys and QuestionnairesABSTRACT
The number of person-to-person transmitted norovirus cases (n = 4,712) in school children in Osaka, Japan, during 2016/17 was the largest since 2012/13. Norovirus outbreaks were reported by 101 schools including 53 nursery schools (1,927 cases), 18 kindergartens (1,086 cases) and 30 elementary schools (1,699 cases). The dominant genotype among outbreaks was GII.P16-GII.2 (57.4%; 58/101), followed by GII.P2-GII.2 (8.9%; 9/101) and GII.P7-GII.6 (5.9%; 6/101). GII.4 was not detected despite dominance in previous years.
Subject(s)
Caliciviridae Infections/epidemiology , Caliciviridae Infections/transmission , Disease Outbreaks , Gastroenteritis/virology , Norovirus/genetics , Adolescent , Caliciviridae Infections/virology , Child , Child, Preschool , Female , Gastroenteritis/epidemiology , Humans , Incidence , Male , Norovirus/classification , Population Surveillance , SeasonsABSTRACT
Analysis of complete capsid sequences of the emerging norovirus GII.17 Kawasaki 308 from 13 countries demonstrated that they originated from a single haplotype since the initial emergence in China in late 2014. Global spread of a sublineage SL2 was identified. A new sublineage SL3 emerged in China in 2016.
Subject(s)
Caliciviridae Infections/epidemiology , Caliciviridae Infections/virology , Gastroenteritis/epidemiology , Gastroenteritis/virology , Norovirus/classification , Caliciviridae Infections/history , Caliciviridae Infections/transmission , Capsid Proteins/genetics , Cluster Analysis , Gastroenteritis/history , Genotype , Global Health , History, 21st Century , Humans , Norovirus/genetics , Phylogeny , Sequence Analysis, DNAABSTRACT
Rotavirus vaccines have been successful in controlling severe diarrhea and have decreased deaths of young children globally. Rotarix and RotaTeq are the two currently available live-attenuated rotavirus vaccines. The vaccine virus can grow in a recipient's gut and spread from the vaccinee to naïve individuals. The potential for the emergence of revertant viruses is a concern with live-attenuated vaccines. We identified a previously healthy infant with severe acute gastroenteritis that was positive for rotavirus in a non-endemic season. A whole genome sequencing revealed that all of the viral genome segments were highly similar to those of the Rotarix virus, with the exception of five amino acid mutations in viral genes that could be associated with virulence. The younger sibling of this patient was administered Rotarix before the onset of disease in this patient, although no gastrointestinal symptoms were reported. Epidemiological data, circumstantial evidence, and the genome analysis suggest that the vaccine virus was transmitted from the vaccinee to the patient. CONCLUSION: This is a severe acute gastroenteritis case most probably attributed to the secondary infection of Rotarix-related virus without underlying diseases. The importance of molecular surveillance of rotavirus infections is discussed. What is Known: ⢠The live-attenuated rotavirus vaccines, Rotarix and RotaTeq, have been successful in controlling severe diarrhea and have decreased deaths of young children globally. ⢠Attenuated vaccine virus can grow in a recipient's gut and spread to naïve individuals and may revert to cause secondary symptomatic infections. What is New: ⢠This is the first report describing a Rotarix-associated secondary infection resulting in severe acute gastroenteritis in an infant without underlying diseases. ⢠Amino acid mutations that might contribute to viral pathogenesis were identified by whole genome sequencing.
Subject(s)
Gastroenteritis/virology , Rotavirus Infections/complications , Rotavirus Vaccines/adverse effects , Acute Disease , Child, Preschool , Diarrhea/virology , Enzyme-Linked Immunosorbent Assay , Female , Humans , Real-Time Polymerase Chain Reaction , Rotavirus/isolation & purification , Severity of Illness Index , Vaccines, Attenuated/adverse effects , Whole Genome SequencingABSTRACT
Human norovirus is a major cause of viral acute gastroenteritis worldwide. However, the transition of endemic norovirus genotypes remains poorly understood. The characteristics of natural immunity against norovirus are unclear because few studies have been performed in the natural infection setting. This prospective 10-year surveillance study of acute gastroenteritis in the province of Osaka, Japan, revealed that norovirus spread shows temporal, geographic, and age group-specific features in the humans. Genogroup II genotype 4 (GII.4) was detected in most sporadic pediatric cases, as well as in foodborne and nursing home outbreaks, respectively. The dominant genotypes in outbreaks at childcare facilities and schools shifted every season and involved GI, GII.2, GII.3, GII.4, and GII.6. Evidence at both the facility and individual levels indicated that genotype-specific herd immunity lasted long enough to influence the endemic norovirus genotype in the next season. Thus, norovirus circulates through human populations in a uniquely dynamic fashion.
Subject(s)
Caliciviridae Infections/epidemiology , Gastroenteritis/epidemiology , Immunity, Herd , Norovirus/immunology , Acute Disease , Adolescent , Caliciviridae Infections/immunology , Child , Child, Preschool , Disease Outbreaks , Epidemiological Monitoring , Gastroenteritis/immunology , Genotype , Humans , Infant , Infant, Newborn , Longitudinal Studies , Norovirus/genetics , Prospective StudiesABSTRACT
A plasmid-based reverse genetics system for human astrovirus type 1 (HAstV1) is examined. Upon transfection into 293T cells, the plasmid vector, which harbors a HAstV1 expression cassette, expressed astroviral RNA that appeared to be capable of viral RNA replication, as indicated by the production of subgenomic RNA and capsid protein expression irrespective of the heterologous 5' ends of the transcribed RNA. Particles infectious to Caco-2 cells were made in this system; however, their infectivity was much lower than would be expected from the amount of particles apparently produced. Using Huh-7 cells as the transfection host with the aim of improving viral capsid processing for virion maturation partially restored the efficiency of infectious particle formation. Our results support the possibility that the DNA transfection process induces a cellular response that targets late, but not early, stages of HAstV1 infection.
Subject(s)
Capsid Proteins/biosynthesis , Mamastrovirus/genetics , Plasmids/genetics , RNA, Viral/genetics , Virus Replication/genetics , Astroviridae Infections/genetics , Astroviridae Infections/virology , Caco-2 Cells , Cell Line , DEAD Box Protein 58 , DEAD-box RNA Helicases/immunology , Gastroenteritis/virology , HEK293 Cells , Humans , Immunity, Innate/immunology , RNA, Viral/biosynthesis , Receptors, Immunologic , Reverse Genetics , Transfection , Virus Assembly/geneticsABSTRACT
We investigated the molecular epidemiology of human norovirus (HuNoV) in all age groups using samples from April 2019 to March 2023, before and after the COVID-19 countermeasures were implemented. GII.2[P16] and GII.4[P31], the prevalent strains in Japan before COVID-19 countermeasures, remained prevalent during the COVID-19 pandemic, except from April to November 2020; in 2021, the prevalence of GII.2[P16] increased among children. Furthermore, there was an increase in the prevalence of GII.4[P16] after December 2022. Phylogenetic analysis of GII.P31 RdRp showed that some strains detected in 2022 belonged to a different cluster of other strains obtained during the present study period, suggesting that HuNoV strains will evolve differently even if they have the same type of RdRp. An analysis of the amino acid sequence of VP1 showed that some antigenic sites of GII.4[P16] were different from those of GII.4[P31]. The present study showed high infectivity of HuNoV despite the COVID-19 countermeasures and revealed changes in the prevalent genotypes and mutations of each genotype. In the future, we will investigate whether GII.4[P16] becomes more prevalent, providing new insights by comparing the new data with those analyzed in the present study.
Subject(s)
COVID-19 , Caliciviridae Infections , Genotype , Norovirus , Phylogeny , Humans , Norovirus/genetics , Norovirus/classification , Japan/epidemiology , Caliciviridae Infections/epidemiology , Caliciviridae Infections/virology , COVID-19/epidemiology , COVID-19/virology , COVID-19/prevention & control , Child , Child, Preschool , Infant , Adult , Adolescent , Middle Aged , Young Adult , SARS-CoV-2/genetics , SARS-CoV-2/classification , Aged , Female , Male , Prevalence , Molecular Epidemiology , Infant, Newborn , Aged, 80 and over , Gastroenteritis/virology , Gastroenteritis/epidemiology , Gastroenteritis/prevention & control , Feces/virologyABSTRACT
Sapoviruses, like noroviruses, are single-stranded positive-sense RNA viruses classified in the family Caliciviridae and are recognized as a causative pathogen of diarrhea in infants and the elderly. Like human norovirus, human sapovirus (HuSaV) has long been difficult to replicate in vitro. Recently, it has been reported that HuSaV can be replicated in vitro by using intestinal epithelial cells (IECs) derived from human tissues and cell lines derived from testicular and duodenal cancers. In this study, we report that multiple genotypes of HuSaV can sufficiently infect and replicate in human-induced pluripotent stem cell-derived IECs. We also show that this HuSaV replication system can be used to investigate the conditions for inactivation of HuSaV by heat and alcohol, and the effects of virus neutralization of antisera obtained by immunization with vaccine antigens, under conditions closer to the living environment. The results of this study confirm that HuSaV can also infect and replicate in human normal IECs regardless of their origin and are expected to contribute to future virological studies.
Subject(s)
Caliciviridae , Induced Pluripotent Stem Cells , Norovirus , Sapovirus , Aged , Infant , Humans , Sapovirus/genetics , Intestines , Epithelial CellsABSTRACT
Sapovirus (SaV) infections are a public health problem because they cause acute gastroenteritis in humans of all ages, both sporadically and as outbreaks. However, only a limited amount of SaV sequence information, especially whole-genome sequences for all the SaV genotypes, is publicly available. Therefore, in this study, we determined the full/near-full-length genomic sequences of 138 SaVs from the 2001 to 2015 seasons in 13 prefectures across Japan. The genogroup GI was predominant (67%, n = 92), followed by genogroups GII (18%, n = 25), GIV (9%, n = 12), and GV (6%, n = 9). Within the GI genogroup, four different genotypes were identified: GI.1 (n = 44), GI.2 (n = 40), GI.3 (n = 7), and GI.5 (n = 1). We then compared these Japanese SaV sequences with 3,119 publicly available human SaV sequences collected from 49 countries over the last 46 years. The results indicated that GI.1, and GI.2 have been the predominant genotypes in Japan, as well as in other countries, over at least four decades. The 138 newly determined Japanese SaV sequences together with the currently available SaV sequences, could facilitate a better understanding of the evolutionary patterns of SaV genotypes.
Subject(s)
Caliciviridae Infections , Sapovirus , Humans , Sapovirus/genetics , Japan/epidemiology , Caliciviridae Infections/epidemiology , Base Sequence , Genotype , Phylogeny , FecesABSTRACT
Several organophosphorus compounds such as organophosphate pesticides (OPPs) and trialkylphosphates (TAPs) are suspected to inhibit cholinesterase activities, to affect endocrine systems or to possibly be carcinogenic. To evaluate their adverse effects on health with chronic exposure in the general population, especially in children, we measured the household exposure to OPPs and TAPs by Japanese children via all exposure pathways and the contribution of indoor air quality. First-morning void urine was collected from subjects aged 6 to 15 years (n = 132), and airborne organophosphorus compounds were sampled in the subject's bedroom for 24 h. Airborne levels of nine OPPs and three TAPs and their urinary metabolites were determined. No significant correlations were detected for any compounds between their airborne concentrations and the urinary excretion amounts of their corresponding metabolites. The estimated daily intakes were as follows (median, µg/kg b.w./d): chlorpyrifos, 0.042; diazinon, 0.067; tri-n-butylphosphate, 0.094. The 95th percentiles of the intakes for fenthion, fenitrothion and the above three compounds did not exceed their reference limit values, although one subject had a daily intake of tri-n-butylphosphate that was about twice its reference limit value. The concentration levels of the urinary metabolite of tri-n-butylphosphate in our subjects tended to be higher than those for children in many other countries. The fractions of the amounts absorbed by inhalation to the amounts absorbed via all of the exposure pathways was only 2.3 % (median) for tri-n-butylphosphate. Inhalation did not seem to contribute very much as an absorption pathway of the organophosphorus compounds in these Japanese children while they were at home. The exposure amounts of OPPs were not suggested to be high enough to adversely affect the health of these children at present on the basis of their daily intakes compared to their reference limit values.
Subject(s)
Air Pollution, Indoor , Chlorpyrifos , Insecticides , Pesticides , Adolescent , Air Pollution, Indoor/analysis , Child , Chlorpyrifos/analysis , Cholinesterases , Diazinon , Environmental Exposure/analysis , Fenitrothion , Fenthion , Humans , Insecticides/analysis , Japan , Organophosphates , Organophosphorus Compounds , Pesticides/analysisABSTRACT
(1) Background: General infection control measures have been implemented at the societal level against COVID-19 since the middle of 2020, namely, hand hygiene, universal masking, and social distancing. The suppressive effect of the social implementation of general infection control measures on pediatric infections has not been systematically assessed. (2) Methods: We addressed this issue based on publicly available data on 11 pediatric infections reported weekly by sentinel sites in Osaka and Iwate prefectures in Japan since 2010. We obtained the 5-year average for 2015-2019 and compared it to the weekly report for 2020-2021. (3) Results: The rate of 6 of the 11 pediatric infections decreased significantly during 2020-2021, regardless of the magnitude of the prevalence of COVID-19 in both areas. However, only RSV infection, one of the six infections, was endemic in 2021. Exanthem subitum was not as affected by COVID-19 countermeasures as other diseases. (4) Conclusions: The social implementation of infectious disease control measures was effective in controling certain infectious diseases in younger age groups, where compliance with the countermeasures should not be as high as that of adults.
ABSTRACT
Passive administration of neutralizing antibodies (Abs) is an attractive strategy for the control of gastrointestinal infections. However, an unanswered practical concern is the need to assure the stability of sufficient amounts of orally administered neutralizing Abs against intestinal pathogens (e.g., norovirus) in the harsh environment of the gastrointestinal tract. To this end, we expressed a single-domain Ab (VHH, nanobody) against norovirus on the cell surface of Lactobacillus, a natural and beneficial commensal component of the gut microbiome. First, we used intestinal epithelial cells generated from human induced pluripotent stem cells to confirm that VHH 1E4 showed neutralizing activity against GII.17 norovirus. We then expressed VHH 1E4 as a cell-wall-anchored form in Lactobacillus paracasei BL23. Flow cytometry confirmed the expression of VHH 1E4 on the surface of lactobacilli, and L. paracasei that expressed VHH 1E4 inhibited the replication of GII.17 norovirus in vitro. We then orally administered VHH 1E4-expressing L. paracasei BL23 to germ-free BALB/c mice and confirmed the presence of lactobacilli with neutralizing activity in the intestine for at least 10 days after administration. Thus, cell-wall-anchored VHH-displaying lactobacilli are attractive oral nanobody deliver vectors for passive immunization against norovirus infection.
ABSTRACT
Several synthetic pyrethroids are suspected to have carcinogenicity or reproductive toxicity. However, there is little knowledge about indoor air pollution in residences or the extent of intake by the residents of the newly developed pyrethroids, transfluthrin, profluthrin, and metofluthrin, although they have been widely used indoors as mosquito repellents and mothproof repellents in recent years. In the present study, the household exposure to pyrethroids through all exposure pathways and the contribution of inhalation pathway in Japanese children were examined by measuring urinary pyrethroid metabolites in the children and the airborne pyrethroids in their residences. Urine excreted first after waking up was collected from subjects aged 6 to 15 years (n = 132), and airborne pyrethroids were sampled in the subjects' bedrooms for 24 h. Nineteen pyrethroids and their nine urinary metabolites were measured. Their daily intakes estimated were as follows (median, ng/kg b.w./d): bifenthrin, 56; transfluthrin, 22; metofluthrin, 11; profluthrin, 0.86. The contribution rates of the amounts absorbed by inhalation to the amounts absorbed via all of the exposure pathways while at home tended to decrease in the following order: profluthrin (median 15%) ≈ transfluthrin (14%) > metofluthrin (1%) > bifenthrin (0.1%). Transfluthrin was considered to be the most notable pyrethroid as an indoor air pollutant. Our study demonstrated widespread exposure to transfluthrin, metofluthrin, profluthrin, and bifenthrin in a sample of Japanese children.
Subject(s)
Air Pollutants , Air Pollution, Indoor , Insect Repellents , Insecticides , Pyrethrins , Adolescent , Air Pollutants/analysis , Child , Humans , Japan , Pyrethrins/analysisABSTRACT
p-Dichlorobenzene (DCB) and naphthalene (NP) used as moth repellents in indoor environments are suspected to be carcinogenic. To evaluate their adverse effects on health with chronic exposure in the general population, especially children, we need to know their amounts absorbed by the body and the relationships between their amounts and air quality in residences. At present, little is known worldwide about them. This study examined the daily intakes of DCB and NP by Japanese children via all exposure pathways and the contribution of indoor air quality to the intakes. First-morning void urine samples from the subjects aged 6 to 15 years and air samples in their bedrooms were collected. Airborne NP and DCB and their urinary metabolites were measured. Significant correlations were detected between their airborne concentrations and the urinary excretion amounts of their corresponding metabolites. The absorption amounts of DCB and NP by inhalation of the children while at home were calculated to be 26 and 2.0 ng/kg b.w./h, respectively, as median values. The daily intake was estimated to be 2.4 and 0.90 µg/kg b.w./d (median), respectively. The fractions (median) of inhalation absorption amounts to overall absorption amounts for DCB and NP were 30% and 5%, respectively. In children living in residences where the indoor air concentrations of these compounds were more than half the level of each guideline value for indoor air quality, the main exposure route for their absorption was considered to be inhalation while at home. The indoor concentrations of DCB exceeded the lifetime excess cancer risk level of 10-4 in 22% of the residences and 10-3 in 9% of them. Our findings indicate the need to further reduce airborne concentrations of DCB in Japanese residences to prevent its adverse effects on the health of Japanese children.
Subject(s)
Air Pollutants , Air Pollution, Indoor , Moths , Air Pollutants/analysis , Air Pollution, Indoor/analysis , Animals , Child , Chlorobenzenes , Humans , Inhalation Exposure , Japan , NaphthalenesABSTRACT
Human norovirus is the leading cause of acute nonbacterial gastroenteritis in people of all ages worldwide. Currently, no licensed norovirus vaccine, pharmaceutical drug, or therapy is available for the control of norovirus infection. Here, we used a rice transgenic system, MucoRice, to produce a variable domain of a llama heavy-chain antibody fragment (VHH) specific for human norovirus (MucoRice-VHH). VHH is a small heat- and acid-stable protein that resembles a monoclonal antibody. Consequently, VHHs have become attractive and useful antibodies (Abs) for oral immunotherapy against intestinal infectious diseases. MucoRice-VHH constructs were generated at high yields in rice seeds by using an overexpression system with RNA interference to suppress the production of the major rice endogenous storage proteins. The average production levels of monomeric VHH (7C6) to GII.4 norovirus and heterodimeric VHH (7C6-1E4) to GII.4 and GII.17 noroviruses in rice seed were 0.54 and 0.28% (w/w), respectively, as phosphate buffered saline (PBS)-soluble VHHs. By using a human norovirus propagation system in human induced pluripotent stem-cell-derived intestinal epithelial cells (IECs), we demonstrated the high neutralizing activity of MucoRice expressing monomeric VHH (7C6) against GII.4 norovirus and of heterodimeric VHH (7C6-1E4) against both GII.4 and GII.17 noroviruses. In addition, MucoRice-VHH (7C6-1E4) retained neutralizing activity even after heat treatment at 90°C for 20 min. These results build a fundamental platform for the continued development of MucoRice-VHH heterodimer as a candidate for oral immunotherapy and for prophylaxis against GII.4 and GII.17 noroviruses in not only healthy adults and children but also immunocompromised patients and the elderly.
ABSTRACT
Some phthalates, which are used mainly as plasticizers, are suspected to be endocrine disruptors. In the present study, daily intakes of phthalates by Japanese children through all exposure pathways and the contribution of indoor air quality to the intakes were examined by measuring urinary phthalate metabolites in the children and the airborne phthalates in their residences. Spot urine samples excreted first after waking up in the morning were collected from the subjects aged 6 to 15 years (n = 132), and airborne phthalates were sampled in the subjects' bedrooms for 24 h. Eight airborne phthalates and their urinary metabolites were determined by gas chromatography/mass spectrometry. The daily intakes of the phthalates estimated were as follows (median, µg/kg b.w./day): dimethyl phthalate (DMP), 0.15; diethyl phthalate (DEP), 0.42; diisobutyl phthalate (DiBP), 1.1; di-n-butyl phthalate (DnBP), 2.2; dicyclohexyl phthalate (DcHP), 0.026; benzylbutyl phthalate (BBzP), 0.032; di(2-ethylhexyl) phthalate (DEHP), 6.3. The 95th percentile (21 µg/kg b.w./day) of the DEHP intakes exceeded the reference doses (RfD, 20 µg/kg b.w./day) of the US Environmental Protection Agency (EPA). DEHP was suggested to be the most notable phthalate from the perspective of adverse effects on the health of Japanese children. On the other hand, DcHP and di-n-hexyl phthalate were not considered to be very important as indoor air pollutants and as internal contaminants for the children. The contribution rates of the amounts absorbed by inhalation to the amounts absorbed via all of the exposure pathways were only 7.9, 4.4, 6.6, 3.2, 0.22, and 1.0% as the median for DMP, DEP, DiBP, DnBP, BBzP, and DEHP, respectively. Therefore, inhalation did not seem to contribute very much as an absorption pathway of the phthalates for Japanese children while at home.